telegraf/plugins/parsers/dropwizard/parser.go

261 lines
7.4 KiB
Go

package dropwizard
import (
"bytes"
"encoding/json"
"fmt"
"log"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal/templating"
"github.com/influxdata/telegraf/metric"
"github.com/tidwall/gjson"
)
var fieldEscaper = strings.NewReplacer("\\", "\\\\", "\"", "\\\"")
var keyEscaper = strings.NewReplacer(" ", "\\ ", ",", "\\,", "=", "\\=")
// Parser parses json inputs containing dropwizard metrics,
// either top-level or embedded inside a json field.
// This parser is using gjon for retrieving paths within the json file.
type Parser struct {
// an optional json path containing the metric registry object
// if left empty, the whole json object is parsed as a metric registry
MetricRegistryPath string
// an optional json path containing the default time of the metrics
// if left empty, or if cannot be parsed the current processing time is used as the time of the metrics
TimePath string
// time format to use for parsing the time field
// defaults to time.RFC3339
TimeFormat string
// an optional json path pointing to a json object with tag key/value pairs
// takes precedence over TagPathsMap
TagsPath string
// an optional map containing tag names as keys and json paths to retrieve the tag values from as values
// used if TagsPath is empty or doesn't return any tags
TagPathsMap map[string]string
// an optional map of default tags to use for metrics
DefaultTags map[string]string
// templating configuration
Separator string
Templates []string
templateEngine *templating.Engine
}
// Parse parses the input bytes to an array of metrics
func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {
metrics := make([]telegraf.Metric, 0)
metricTime, err := p.parseTime(buf)
if err != nil {
return nil, err
}
dwr, err := p.unmarshalMetrics(buf)
if err != nil {
return nil, err
}
metrics = p.readDWMetrics("counter", dwr["counters"], metrics, metricTime)
metrics = p.readDWMetrics("meter", dwr["meters"], metrics, metricTime)
metrics = p.readDWMetrics("gauge", dwr["gauges"], metrics, metricTime)
metrics = p.readDWMetrics("histogram", dwr["histograms"], metrics, metricTime)
metrics = p.readDWMetrics("timer", dwr["timers"], metrics, metricTime)
jsonTags := p.readTags(buf)
// fill json tags first
if len(jsonTags) > 0 {
for _, m := range metrics {
for k, v := range jsonTags {
// only set the tag if it doesn't already exist:
if !m.HasTag(k) {
m.AddTag(k, v)
}
}
}
}
// fill default tags last
if len(p.DefaultTags) > 0 {
for _, m := range metrics {
for k, v := range p.DefaultTags {
// only set the default tag if it doesn't already exist:
if !m.HasTag(k) {
m.AddTag(k, v)
}
}
}
}
return metrics, nil
}
// InitTemplating initializes the templating support
func (p *Parser) InitTemplating() error {
if len(p.Templates) > 0 {
defaultTemplate, _ := templating.NewDefaultTemplateWithPattern("measurement*")
templateEngine, err := templating.NewEngine(p.Separator, defaultTemplate, p.Templates)
p.templateEngine = templateEngine
return err
}
return nil
}
// ParseLine is not supported by the dropwizard format
func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
return nil, fmt.Errorf("ParseLine not supported: %s, for data format: dropwizard", line)
}
// SetDefaultTags sets the default tags
func (p *Parser) SetDefaultTags(tags map[string]string) {
p.DefaultTags = tags
}
func (p *Parser) readTags(buf []byte) map[string]string {
if p.TagsPath != "" {
var tagsBytes []byte
tagsResult := gjson.GetBytes(buf, p.TagsPath)
if tagsResult.Index > 0 {
tagsBytes = buf[tagsResult.Index : tagsResult.Index+len(tagsResult.Raw)]
} else {
tagsBytes = []byte(tagsResult.Raw)
}
var tags map[string]string
err := json.Unmarshal(tagsBytes, &tags)
if err != nil {
log.Printf("W! failed to parse tags from JSON path '%s': %s\n", p.TagsPath, err)
} else if len(tags) > 0 {
return tags
}
}
tags := make(map[string]string)
for tagKey, jsonPath := range p.TagPathsMap {
tags[tagKey] = gjson.GetBytes(buf, jsonPath).String()
}
return tags
}
func (p *Parser) parseTime(buf []byte) (time.Time, error) {
if p.TimePath != "" {
timeFormat := p.TimeFormat
if timeFormat == "" {
timeFormat = time.RFC3339
}
timeString := gjson.GetBytes(buf, p.TimePath).String()
if timeString == "" {
err := fmt.Errorf("time not found in JSON path %s", p.TimePath)
return time.Now().UTC(), err
}
t, err := time.Parse(timeFormat, timeString)
if err != nil {
err = fmt.Errorf("time %s cannot be parsed with format %s, %s", timeString, timeFormat, err)
return time.Now().UTC(), err
}
return t.UTC(), nil
}
return time.Now().UTC(), nil
}
func (p *Parser) unmarshalMetrics(buf []byte) (map[string]interface{}, error) {
var registryBytes []byte
if p.MetricRegistryPath != "" {
regResult := gjson.GetBytes(buf, p.MetricRegistryPath)
if regResult.Index > 0 {
registryBytes = buf[regResult.Index : regResult.Index+len(regResult.Raw)]
} else {
registryBytes = []byte(regResult.Raw)
}
if len(registryBytes) == 0 {
err := fmt.Errorf("metric registry not found in JSON path %s", p.MetricRegistryPath)
return nil, err
}
} else {
registryBytes = buf
}
var jsonOut map[string]interface{}
err := json.Unmarshal(registryBytes, &jsonOut)
if err != nil {
err = fmt.Errorf("unable to parse dropwizard metric registry from JSON document, %s", err)
return nil, err
}
return jsonOut, nil
}
func (p *Parser) readDWMetrics(metricType string, dwms interface{}, metrics []telegraf.Metric, time time.Time) []telegraf.Metric {
switch dwmsTyped := dwms.(type) {
case map[string]interface{}:
var metricsBuffer bytes.Buffer
for dwmName, dwmFields := range dwmsTyped {
measurementName := dwmName
tags := make(map[string]string)
fieldPrefix := ""
if p.templateEngine != nil {
measurementName, tags, fieldPrefix, _ = p.templateEngine.Apply(dwmName)
if len(fieldPrefix) > 0 {
fieldPrefix = fmt.Sprintf("%s%s", fieldPrefix, p.Separator)
}
}
tags["metric_type"] = metricType
measurementWithTags := measurementName
for tagName, tagValue := range tags {
tagKeyValue := fmt.Sprintf("%s=%s", keyEscaper.Replace(tagName), keyEscaper.Replace(tagValue))
measurementWithTags = fmt.Sprintf("%s,%s", measurementWithTags, tagKeyValue)
}
fields := make([]string, 0)
switch t := dwmFields.(type) {
case map[string]interface{}: // json object
for fieldName, fieldValue := range t {
key := keyEscaper.Replace(fieldPrefix + fieldName)
switch v := fieldValue.(type) {
case float64:
fields = append(fields, fmt.Sprintf("%s=%f", key, v))
case string:
fields = append(fields, fmt.Sprintf("%s=\"%s\"", key, fieldEscaper.Replace(v)))
case bool:
fields = append(fields, fmt.Sprintf("%s=%t", key, v))
default: // ignore
}
}
default: // ignore
}
metricsBuffer.WriteString(fmt.Sprintf("%s,metric_type=%s ", measurementWithTags, metricType))
metricsBuffer.WriteString(strings.Join(fields, ","))
metricsBuffer.WriteString("\n")
}
newMetrics, err := metric.ParseWithDefaultTime(metricsBuffer.Bytes(), time)
if err != nil {
log.Printf("W! failed to create metric of type '%s': %s\n", metricType, err)
}
return append(metrics, newMetrics...)
default:
return metrics
}
}
func arraymap(vs []string, f func(string) string) []string {
vsm := make([]string, len(vs))
for i, v := range vs {
vsm[i] = f(v)
}
return vsm
}